The effect of stationary ultraviolet excitation on the optical properties of electrochemically self-assembled semiconductor nanowires

The optical behavior of electrochemically self-assembled nanowire arrays excited by stationary ultraviolet light is investigated. The wires are fabricated by electrodepositing CdS, ZnO, and ZnSe in anodic porous alumina templates with 50, 25, and 10 nm diameter pores. We have developed a theoretical model to calculate nanowire permittivity, refractive index, and absorption coefficient under such stationary excitation. This model is incorporated in an electromagnetic wave simulation to obtain the optical response of the array of wires. The behavior is also investigated experimentally using a pump-probe excitation scheme in an optical interferometer. We report a strong nonmonotonic optical activity as a function of wire diameter in the nanowire arrays. This result implies a sharp increase in the optically pumped change in refractive index and permittivity in narrower nanowires. (c) 2007 American Institute of Physics.